The following issued patents and patent publications provide potentially relevant background material and are all incorporated by reference in their entirety: U.S. Pat. No. 4,974,922 A (Mori), WO92/11495A1 (Moeller), GB2485332 A (Melling), GB2287122 A (Gregson), U.S. Pat. No. 4,798,444 A (McLean), US 20120154941 A1 (Zalevsky), U.S. Pat. No. 5,089,055 A (NAKAMURA TAKASHI), WO 2009/028868 A2 (O SE DAE) US 20150255658 A1 (MORGAN), 20160276514 A1 (Simavoryan), 20160336467 A1 (JANET), US2011/0232719 A1 (FREDA), US2013/0118550 A1 (SAHIN), U.S. Pat. No. 4,117,829 (GROSS), and 20180017227 A1 (Prins).